Fixing chaincore and core unit tests

[MurashovVen]

Fixed tests:

1. Removing logs from client_test
2. Removing logs from node_test
3. Removing logs from round_test and adding error checking
4. Removing logs from wallet_test and minor code refactoring
5. Removing logs from dkg_test and minor code refactoring
6. Removing logs from codec_test
7. Tests of util package (merkle_patricia_trie_test, merkle_patricia_trie2_test, merkle_patricia_trie3_test, merkle_trie_test, mpt_nodedb_test):
   removing logs, code refactoring .
8. Removing old tests from memorystore and adding new
9. Removing old tests from persistencestore and adding new
10. Test of encryption package (bls0chain_test, bls0chain_aggregate_test, bls0chain_splittable_test, ed25519_test, encryption_test):
    removing logs

Also added mocks package which includes mocks, used in added tests.

[Sriep]

All new unit tests should be checked with the -race option to make sure they are no contributing race issues.

On running the tests with the -race options two tests modified here produced errors.

• code/go/0chain.net/core/common/codec_test.go Preexisting code. Probably can be handled in Investigate ToMsgpack for race issues. #200, as the whole test needs a rethink.
• code/go/0chain.net/core/memorystore/store_test.go This is a new test and should not produce confounding race errors. If the race errors here are due to the unit test, they should be fixed. If they are due to the production code; Well done! The description needs updating and an issue raised to fix the race issues.

[MurashovVen]

These errors occur because memorystore.DefaultPool isn't protected from concurrent access. We can resolve these race errors by adding global mutex that protects DefaultPool.
Also, trackCollection method runs CollectionTrimmer as a goroutine that needs access to DefaultPool. It makes race test errors and I think we can resolve it by locking mutex when CollectionTrimmer calls GetEntityConnection func.

[Sriep]

Added issue #242, to fix memorystore.DefaultPool.

With this, can we close PR #87 Adding core unit tests?

[MurashovVen]

Added issue #242, to fix memorystore.DefaultPool.

With this, can we close PR #87 Adding core unit tests?

Only partially. There are also tests that I would like to decompose into packages and make appropriate PRs:

• cache
• common
• datastore
• ememorystore
• encryption
• logging
• metric
• util